------- Additional Comments From law at redhat dot com 2005-02-10 18:01 -------
Subject: Re: [4.0 Regression] Poor quality
code after loop unrolling.
On Thu, 2005-02-10 at 12:12 +0100, Zdenek Dvorak wrote:
> > In comment #3 Zdenek said "Possibly even better would be to add generation
> > of
> > autoincrements to loop optimizer, but this would require fixing cse so that
> > it
> > handles them correctly." Zdenek, can you elaborate on why CSE needs
> > fixing?
>
> cse does not handle autoincrements. I have no idea what's the problem
> there, it is just what I was told when I asked for the possibility to
> move the autoinc creation pass last time. Anyone has more precise
> information about the nature of the problem?
It's been about a decade since I looked at cse vs autoincrements, so
the details have faded from memory. [The original context I found the
problem was in an attempt to run cse after reload. ]
Anyway, from a 30 second look at CSE the first thing that jumps out at
me is I don't think we would invalidate objects in the hash table which
are auto-incremented.
Jeff
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19078
